Search results

1 – 10 of over 2000
Article
Publication date: 18 December 2019

Muhammad Taimoor and Li Aijun

The purpose of this paper is to propose an adaptive neural-sliding mode-based observer for the estimation and reconstruction of unknown faults and disturbances for…

Abstract

Purpose

The purpose of this paper is to propose an adaptive neural-sliding mode-based observer for the estimation and reconstruction of unknown faults and disturbances for time-varying nonlinear systems such as aircraft, to ensure preciseness in the diagnosis of fault magnitude as well as the shape without enhancement of system complexity and cost. Fault-tolerant control (FTC) strategy based on adaptive neural-sliding mode is also proposed in the existence of faults for ensuring the stability of the faulty system.

Design/methodology/approach

In this paper, three strategies are presented: adaptive radial basis functions neural network (ARBFNN), conventional radial basis functions neural network (CRBFNN) and integral-chain differentiator. For the purpose of enhancement of fault diagnosis and isolation, a new sliding mode-based concept is introduced for the weight updating parameters of radial basis functions neural network (RBFNN).The main objective of updating the weight parameters adaptively is to enhance the effectiveness of fault diagnosis and isolation without increasing the computational complexities of the system. Results depict the effectiveness of the proposed ARBFNN approach in fault detection (FD) and approximation compared to CRBFNN, integral-chain differentiator and schemes existing in literature. In the second step, the FTC strategy is presented separately for each observer in the presence of unknown faults and failures for ensuring the stability of the system, which is validated on Boeing 747 100/200 aircraft.

Findings

The proposed adaptive neural-sliding mode approach is investigated, which depicts more effectiveness in numerous situations such as faults, disturbances and uncertainties compared to algorithms used in literature. In this paper, both the fault approximation and isolation and the fault tolerance approaches are studied.

Practical implications

For the enhancement of safety level as well as for avoiding any kind of damage, timely FD and fault tolerance have always had a significant role; therefore, the algorithms proposed in this research ensure the tolerance of faults and failures, which plays a vital role in practical life for avoiding any kind of damage.

Originality/value

In this study, a new neural-sliding mode concept is adopted for the adaptive faults approximation and reconstruction, and then the FTC algorithms are studied for each observer separately, whereas in previous studies, only the fault detection and isolation (FDI) or the fault tolerance problems were studied. Results demonstrate the effectiveness of the proposed strategy compared to the approaches given in the literature.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 2
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 1 April 1994

Kamal A. Mehdi and J.M. Kontoleon

Presents an overview of memory chip yield enhancement techniques byinjection of fault tolerance. As memory chips are more prone to defects,the yield of good chips from a…

525

Abstract

Presents an overview of memory chip yield enhancement techniques by injection of fault tolerance. As memory chips are more prone to defects, the yield of good chips from a silicon wafer governs their production cost. As shown, most fault tolerance techniques assume a relatively large area overhead which results in additional costs in terms of the silicon used as well as the lower number of chips/wafers produced. Proper management of fault tolerance, as by the word redundancy approach, adds an almost negligible area overhead to the chip and leads to considerably higher yields.

Details

International Journal of Quality & Reliability Management, vol. 11 no. 3
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 1 March 2001

Nong Ye

Intrusions exploit vulnerabilities and introduce external disturbances into information systems to compromise security attributes of information systems such as…

Abstract

Intrusions exploit vulnerabilities and introduce external disturbances into information systems to compromise security attributes of information systems such as availability, integrity, and confidentiality. Intrusions into information systems cause faults of software and hardware components in information systems, which then lead to errors and failures of system performance. Intrusion tolerance requires information systems to function correctly in a timely manner even under impact of intrusions. In this paper, we discuss causes, chain effects and barriers of intrusions into information systems, and reveal roles that various information security techniques play in intrusion tolerance. We present two robust intrusion tolerance methods through fault masking: Taguchi’s robust method for system configuration and sharing of resources via an information infrastructure for redundancy.

Details

Information Management & Computer Security, vol. 9 no. 1
Type: Research Article
ISSN: 0968-5227

Keywords

Article
Publication date: 1 September 2006

Mehmet Dede and Sabri Tosunoglu

The objective of this study is to enhance the usage of teleoperation fields, such as in nuclear site decommissioning or nuclear waste disposal, by designing a stable…

Abstract

Purpose

The objective of this study is to enhance the usage of teleoperation fields, such as in nuclear site decommissioning or nuclear waste disposal, by designing a stable, dependable and fault‐tolerant teleoperation system in the face of “extraordinary” conditions. These “extraordinary” conditions can be classified as variable time delays in communications lines, usage of different robotic systems, component failures and changes in the system parameters during task execution.

Design/methodology/approach

This paper first gives a review of teleoperation systems developed earlier. Later, fault tolerance is proposed for use in teleoperation systems at the processor, actuator, sub‐system, and system levels. Position/force control algorithms are recommended to address stability issues when there is a loss in communications. Various other controls are also introduced to overcome the instability experienced when there is a time delay in the communications line.

Findings

Finally, this work summarizes the teleoperation system architecture and controller design options in terms of a flowchart to help in the conceptual design of such systems.

Originality/value

The impact of these new designs and algorithms will be to expand the limits and boundaries of teleoperation and a widening of its utilization area. Enhanced operation of these systems will improve system reliability and even encourage their use in more critical and diverse applications.

Details

Industrial Robot: An International Journal, vol. 33 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 24 August 2021

Vipin Sharma, Abdul Q. Ansari and Rajesh Mishra

The purpose of this paper is to design a efficient layout of Multistage interconnection network which has cost effective solution with high reliability and fault-tolerence…

Abstract

Purpose

The purpose of this paper is to design a efficient layout of Multistage interconnection network which has cost effective solution with high reliability and fault-tolerence capability. For parallel computation, various multistage interconnection networks (MINs) have been discussed hitherto in the literature, however, these networks always required further improvement in reliability and fault-tolerance capability. The fault-tolerance capability of the network can be achieved by increasing the number of disjoint paths as a result the reliability of the interconnection networks is also improved.

Design/methodology/approach

This proposed design is a modification of gamma interconnection network (GIN) and three disjoint path gamma interconnection network (3-DGIN). It has a total seven number of paths for all tag values which is uniform out of these seven paths, three paths are disjoint paths which increase the fault tolerance capability by two faults. Due to the presence of more paths than the GIN and 3-DGIN, this proposed design is more reliable.

Findings

In this study, a new design layout of a MIN has been proposed which provides three disjoint paths and uniformity in terms of an equal number of paths for all source-destination (S-D) pairs. The new layout contains fewer nodes as compared to GIN and 3-DGIN. This design provides a symmetrical structure, low cost, better terminal reliability and provides an equal number of paths for all tag values (|S-D|) when compared with existing MINs of this class.

Originality/value

A new design layout of MINs has been purposed and its two terminal reliability is calculated with the help of the reliability block diagram technique.

Details

International Journal of Pervasive Computing and Communications, vol. 17 no. 4
Type: Research Article
ISSN: 1742-7371

Keywords

Article
Publication date: 16 August 2021

Wenhua Huang, Juan Ren, Jinglong Jiang and J. Cheng

Quantum-dot Cellular Automata (QCA) is a new nano-scale transistor-less computing model. To address the scaling limitations of complementary-metal-oxide-semiconductor…

67

Abstract

Purpose

Quantum-dot Cellular Automata (QCA) is a new nano-scale transistor-less computing model. To address the scaling limitations of complementary-metal-oxide-semiconductor technology, QCA seeks to produce general computation with better results in terms of size, switching speed, energy and fault-tolerant at the nano-scale. Currently, binary information is interpreted in this technology, relying on the distribution of the arrangement of electrons in chemical molecules. Using the coplanar topology in the design of a fault-tolerant digital comparator can improve the comparator’s performance. This paper aims to present the coplanar design of a fault-tolerant digital comparator based on the majority and inverter gate in the QCA.

Design/methodology/approach

As the digital comparator is one of the essential digital circuits, in the present study, a new fault-tolerant architecture is proposed for a digital comparator based on QCA. The proposed coplanar design is realized using coplanar inverters and majority gates. The QCADesigner 2.0.3 simulator is used to simulate the suggested new fault-tolerant coplanar digital comparator.

Findings

Four elements, including cell misalignment, cell missing, extra cell and cell dislocation, are evaluated and analyzed in QCADesigner 2.0.3. The outcomes of the study demonstrate that the logical function of the built circuit is accurate. In the presence of a single missed defect, this fault-tolerant digital comparator architecture will achieve 100% fault tolerance. Also, this comparator is above 90% fault-tolerant under single-cell displacement faults and is above 95% fault-tolerant under single-cell missing defects.

Originality/value

A novel structure for the fault-tolerant digital comparator in the QCA technology was proposed used by coplanar majority and inverter. Also, the performance metrics and obtained results establish that the coplanar design can be used in the QCA circuits to produce optimized and fault-tolerant circuits.

Details

Microelectronics International, vol. 38 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 February 2021

Chi-Chun Chen, Jian-Hong Wang, Hsing-Wen Wang and Jie Zhang

This research proposes an innovative fault-tolerant media content list management technology applied to the smart robot domain.

Abstract

Purpose

This research proposes an innovative fault-tolerant media content list management technology applied to the smart robot domain.

Design/methodology/approach

A fault tolerant Content List Management Unit (CLMU) for real-time streaming systems focusing on smart robot claw machines is proposed to synchronize and manage the hyperlink stored on media servers. The fault-tolerant mechanism is realized by the self-healing method. A media server allows exchanging the hyperlink within the network through the CLMU mechanism.

Findings

Internet users can access the current multimedia information, and the multimedia information list can be rearranged appropriately. Furthermore, the service of the proposed multimedia system should be uninterrupted even when the master media server fails. Therefore, one of the slave media servers enables the Content List Service (CLS) of the proposed CLMU and replaces the defunct master media server.

Originality/value

The recovery time is less than 1.5 seconds. The multimedia transmission is not interrupted while any one of the media servers keeps functioning. The proposed method can serve to stabilize the system of media servers in a smart robot domain.

Details

Library Hi Tech, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0737-8831

Keywords

Article
Publication date: 6 July 2015

Mohammad Ghesmat and Akbar Khalkhali

There are high expectations for reliability, safety and fault tolerance are high in chemical plants. Control systems are capable of potential faults in the plant…

Abstract

Purpose

There are high expectations for reliability, safety and fault tolerance are high in chemical plants. Control systems are capable of potential faults in the plant processing systems. This paper proposes is a new Fault Tolerant Control (FTC) system to identify the probable fault occurrences in the plant.

Design/methodology/approach

A Fault Diagnosis and Isolation (FDI) module has been devised based on the estimated state of system. An Unscented Kalman Filter (UKF) is the main innovation of the FDI module to identify the faults. A Multi-Sensor Data Fusion algorithm is utilized to integrate the UKF output data to enhance fault identification. The UKF employs an augmented state vector to estimate system states and faults simultaneously. A control mechanism is designed to compensate for the undesirable effects of the detected faults.

Findings

The performance of the Nonlinear Model Predictive Controller (NMPC) without any fault compensation is compared with the proposed FTC scheme under different fault scenarios. Analysis of the simulation results indicates that the FDI method is able to identify the faults accurately. The proposed FTC approach facilitates recovery of the closed loop performance after the faults have been isolated.

Originality/value

A significant contribution of the paper is the design of an FTC system by using UKF to estimate faults and enhance the accuracy of data. This is done by applying a data fusion algorithm and controlling the system by the NMPC after eliminating the effects of faults.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Open Access
Article
Publication date: 28 December 2020

Qinjie Yang, Guozhe Shen, Chao Liu, Zheng Wang, Kai Zheng and Rencheng Zheng

Steer-by-wire (SBW) system mainly relies on sensors, controllers and motors to replace the traditionally mechanical transmission mechanism to realize steering functions…

Abstract

Purpose

Steer-by-wire (SBW) system mainly relies on sensors, controllers and motors to replace the traditionally mechanical transmission mechanism to realize steering functions. However, the sensors in the SBW system are particularly vulnerable to external influences, which can cause systemic faults, leading to poor steering performance and even system instability. Therefore, this paper aims to adopt a fault-tolerant control method to solve the safety problem of the SBW system caused by sensors failure.

Design/methodology/approach

This paper proposes an active fault-tolerant control framework to deal with sensors failure in the SBW system by hierarchically introducing fault observer, fault estimator, fault reconstructor. Firstly, the fault observer is used to obtain the observation output of the SBW system and then obtain the residual between the observation output and the SBW system output. And then judge whether the SBW system fails according to the residual. Secondly, dependent on the residual obtained by the fault observer, a fault estimator is designed using bounded real lemma and regional pole configuration to estimate the amplitude and time-varying characteristics of the faulty sensor. Eventually, a fault reconstructor is designed based on the estimation value of sensors fault obtained by the fault estimator and SBW system output to tolerate the faulty sensor.

Findings

The numerical analysis shows that the fault observer can be rapidly activated to detect the fault while the sensors fault occurs. Moreover, the estimation accuracy of the fault estimator can reach to 98%, and the fault reconstructor can make the faulty SBW system to retain the steering characteristics, comparing to those of the fault-free SBW system. In addition, it was verified for the feasibility and effectiveness of the proposed control framework.

Research limitations/implications

As the SBW fault diagnosis and fault-tolerant control in this paper only carry out numerical simulation research on sensors faults in matrix and laboratory/Simulink, the subsequent hardware in the loop test is needed for further verification.

Originality/value

Aiming at the SBW system with parameter perturbation and sensors failure, this paper proposes an active fault-tolerant control framework, which integrates fault observer, fault estimator and fault reconstructor so that the steering performance of SBW system with sensors faults is basically consistent with that of the fault-free SBW system.

Details

Journal of Intelligent and Connected Vehicles, vol. 4 no. 1
Type: Research Article
ISSN: 2399-9802

Keywords

Article
Publication date: 16 October 2018

Zhipeng Wang, Zhiqin Qian, Ziye Song, Hongzhou Liu, Wenjun Zhang and Zhuming Bi

Even though multi-rotor aircrafts are becoming more and more prevalent in the fields of aerial photography, agricultural spraying, disaster searching and rescuing, how to…

70

Abstract

Purpose

Even though multi-rotor aircrafts are becoming more and more prevalent in the fields of aerial photography, agricultural spraying, disaster searching and rescuing, how to achieve higher reliability and robustness of an aircraft still poses a big challenge. It is not a rare case that a multi-rotor aircraft is severely damaged or crushed when an actuator or sensor is malfunctioned. This paper aims at the resilience of an aircraft when a rotor is malfunctioned.

Design/methodology/approach

The reliability of a multi-rotor aircraft can be measured in terms of stability, robustness, resilience and fault tolerance. All of these four aspects are taken into consideration to improve overall reliability of aircrafts. When a rotor malfunction occurs, the control algorithm is cable of adjusting the operation conditions of the rest of rotors to achieve system stability.

Findings

In this paper, the authors first present a research topic on the development of a resilient multi-robot aircraft. A multi-rotor aircraft usually possesses more actuated motions than the required degrees of freedom.

Originality/value

The authors proposed to equip the multi-rotor aircraft with malfunction detecting sensors, and they developed the self-repairing algorithm to re-stabilize the aircraft when a malfunction of a rotor occurs. The design concept and methods were implemented on an eight-rotor aircraft, and the performance of the proposed instrumentation and self-repairing algorithm have been verified and validated.

Details

Industrial Robot: An International Journal, vol. 45 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

1 – 10 of over 2000